In a work machine such as a hydraulic excavator provided with a plurality of hydraulic actuators, there exists a hydraulic control unit that is, in order to obtain a fixed operability irrespective of the weight (front weight) of a work arm, structured so as to calculate a flow rate to be distributed from a hydraulic pump to each hydraulic actuator and control the flow rate by a proportional solenoid pressure reducing valve (see Patent Document 1 Japanese Laid-Open Patent Publication No. 2000-145720 (“JP '720”), e.g., Pages 3-4, FIG. 6).